This application pertains to the art of dynamoelectric conversion apparatus and more particularly to an apparatus for converting mechanical energy into electrical energy. The invention is particularly applicable to generators for generating a relatively high current with a relatively low voltage and will be described with particular reference thereto. It will be appreciated, however, that the invention has broader applications such as AC or DC power generation with various voltage and current relationships, and the like.
Current generators have included a rotor which is moved with respect to a magnetic field. The rotor, must commonly, comprises a plurality of coil windings which may be wound around a thin nonmagnetic member, note for example U.S. Pat. No. 2,860,267 to Hayes. Some dynamoelectric machines have rotors constructed of a tubular nonmetallic material supporting windings of a printed circuit type, note for example U.S. Pat. No. 3,668,452, issued Apr. 5, 1971 to P. Y. Hu. See also U.S. Pat. No. 3,259,768, issued July 5, 1966 to R. P. Burr.
The prior art rotor constructions present several problems. The cross-sectional area of coil-wound rotors is limited by two factors. The first factor is that for a given magnetic polar pair gap, the size of the conductive coil cross-sectional area is limited by the necessity of a nonconducting supporting material. The second cross-sectional area limiting factor is the configuration of the coils. Coils having a circular cross section do not achieve the most efficient utilization of the space within the magnetic polar pair gap. In the case of the printed circuit type windings, the cross-sectional area of the conductors is limited by both the presence of the nonconducting supporting material and by the inherent thinness of the printed circuit type windings.
The present invention is also an improvement over the D.C. generator shown in my prior U.S. Pat. No. 4,051,402, issued Sept. 27, 1977. That patent utilized a brush for each polar pair of magnetic members. Because brushes have a high resistance, they absorb energy from the current flowing through them reducing the efficiency of the generator. Further the brushes contacted the rotor cylinder directly necessitating replacement of the whole cylinder when the wear became excessive.
The present invention contemplates a new and improved dynamoelectric apparatus which overcomes the above-referenced problems and others. The present invention provides a current generator which is very efficient in its conversion of mechanical energy to electric power.